The
intricate properties of the fingertips have been mimicked and recreated
using semiconductor devices in what researchers hope will lead to the
development of advanced surgical gloves.

           

The
devices, shown to be capable of responding with high precision to the
stresses and strains associated with touch and finger movement, are a
step towards the creation of surgical gloves for use in medical
procedures such as local ablations and ultrasound scans.

Researchers
from the University of Illinois at Urbana-Champaign, Northwestern
University and Dalian University of Technology have published their
study this week in IOP Publishing’s journal Nanotechnology.

Offering
guidelines to the creation of these electrotactile stimulation devices
for use on surgeons’ fingertips, their paper describes the materials,
fabrication strategies and device designs, using ultrathin, stretchable,
silicon-based electronics and soft sensors that can be mounted onto an
artificial ‘skin’ and fitted to fingertips.

“Imagine
the ability to sense the electrical properties of tissue, and then
locally remove that tissue, precisely by local ablation, all via the
fingertips using smart surgical gloves. Alternatively, or perhaps in
addition, ultrasound imaging could be possible,” said co-author of the
study Professor John Rogers.

The
researchers suggest that the new technology could open up possibilities
for surgical robots that can interact, in a soft contacting mode, with
their surroundings through touch.

The
electronic circuit on the ‘skin’ is made of patterns of gold conductive
lines and ultrathin sheets of silicon, integrated onto a flexible
polymer called polyimide. The sheet is then etched into an open mesh
geometry and transferred to a thin sheet of silicone rubber moulded into
the precise shape of a finger.

This
electronic ‘skin’, or finger cuff, was designed to measure the stresses
and strains at the fingertip by measuring the change in capacitance—the
ability to store electrical charge—of pairs of microelectrodes in the
circuit.  Applied forces decreased the spacing in the skin which, in
turn, increased the capacitance.

The
fingertip device could also be fitted with sensors for measuring motion
and temperature, with small-scale heaters as actuators for ablation and
other related operations.

The
researchers experimented with having the electronics on the inside of
the device, in contact with wearer’s skin, and also on the outside. They
believe that because the device exploits materials and fabrication
techniques adopted from the established semiconductor industry, the
processes can be scaled for realistic use at reasonable cost.

“Perhaps
the most important result is that we are able to incorporate
multifunctional, silicon semiconductor device technologies into the form
of soft, three-dimensional, form-fitting skins, suitable for
integration not only with the fingertips but also other parts of the
body,” continued Rogers.

Indeed,
the researchers now intend to create a ‘skin’ for integration on other
parts of the body, such as the heart.  In this case, a device would
envelop the entire 3D surface of the heart, like a sock, to provide
various sensing and actuating functions, providing advanced surgical and
diagnostic devices relevant to cardiac arrhythmias.

Future challenges include creating materials and schemes to provide the device with wireless data and power.

Source: Institute of Physics